97 Aerostar running hot
 

OK, back to the beast again. On the road, temperature is just slightly above mid-range, where it has always been. When stopped with engine idling, the temp slowly increases. If I set for more than a few minutes, it approaches max full scale. When I drive off, it comes back to normal.

Another symptom - that may or may not be normal or related - is when I start up cold, it takes a good 10 minutes to come up to temperature. Other car takes about 2 minutes.

R/R fan clutch -- no change.

97 Aerostar running hot
 

Sounds like the thermostatic radiator valve that opens as the engine warms
up is jammed shut. When the car is running down the road, there's enough air
flow to keep the engine cool.

Or, the valve's "opening" temperature has become too high, and it won't open
up until the idling engine gets really hot.

97 Aerostar running hot
 

On Aug 13, 10:56*am, "Guv Bob"
wrote:
OK, back to the beast again. *On the road, temperature is just slightly above mid-range, where it has always been. * When stopped with engine idling, the temp slowly increases. * If I set for more than a few minutes, it approaches max full scale. * When I drive off, it comes back to normal..

Another symptom - that may or may not be normal or related - is when I start up cold, it takes a good 10 minutes to come up to temperature. *Other car takes about 2 minutes.

R/R fan clutch -- *no change.

Do you see the fan spinning?

What happens if you turn the heat on while you idle?

97 Aerostar running hot
 

"William Sommerwerck" wrote in message
...
Sounds like the thermostatic radiator valve that opens as the engine warms
up is jammed shut. When the car is running down the road, there's enough
air
flow to keep the engine cool.

Or, the valve's "opening" temperature has become too high, and it won't
open
up until the idling engine gets really hot.


That was my first thought as well, but modern 'stats are usually designed to
fail 'safe' i.e. open. How about an air lock? Some engines are very fussy
about getting the head full of water. I used to own a 5 cylinder Passat, and
you had to jack one side of the vehicle up really high to get all of the air
out, otherwise, it did just the sort of crap that you are describing ...

Arfa

97 Aerostar running hot
 

Guv Bob wrote:

OK, back to the beast again. On the road, temperature is just slightly
above mid-range, where it has always been. When stopped with engine
idling, the temp slowly increases. If I set for more than a few minutes,
it approaches max full scale. When I drive off, it comes back to normal.

Another symptom - that may or may not be normal or related - is when I
start up cold, it takes a good 10 minutes to come up to temperature.
Other car takes about 2 minutes.

R/R fan clutch -- no change.
Are you sure the fan clutch is good? If you rev the engine to 3000 RPM
or so, the fan should really roar, especially when the engine is hot.
Since the problem occurs at idle, maybe you can spray a spot of paint
on one fan blade, so you can gauge the fan RPM. The fan clutches are
supposed to couple well at low RPM, and when hot, and less well when
cool and at higher RPM. I'm assuming a fluid clutch.

Jon

97 Aerostar running hot
 

First of all was the coolant filled using the proper procedure ? If not there could be an air pocket.

Second a Tstat cannot be designed to failsafe open, and EVERY time that engine overheats the stat could go bad. Luckily they are cheap.

Third the radiator could be clogged at the bottom.

To check it out, first of all run it with the radiator cap off, I DO NOT mean the reservoir, I mean the radiator itself. Some actully do not have one but that vehicle should. Fill the water and rev the gas using the throttle. If the water comes up you need a head gasket at least. If the water does nothing try a water pump, I have actually seen them with broken impellors internally.

If the water does suck down, regardless of if the Tstat is open or not, suspect the radiator itself. It could be half clogged. You have no way of knowing except maybe to run the vehicle until it gets really hot and compare the temperature of the top and bottom of the radiator. The top will always be hotter but, then you have to guage how much. Let's put it this way, if it is about to boil over and you can put your hand on the bottom of it, it's clogged. However on that vehicle I dount you can do that.

Got one of those heat detecting gun jobbies ?

Anyway, unless you have an EXTREMELY wierd engine management problem or a head or head gasket leakage, I have the solution. I have done it a few times because you don't **** around with two things - cooling and oil.

If I verified that there was no head/gasket problems I would get a recored radiator, a new water pump, thermostat as well as hoses. And a belt for the hell of it. Put it all in at once and then follow the proper filling procedure.

First of all in my cars, even though it is not recommended, fukum - pure antifreeze. You put it in and then start it. You run it as it sucks it down. THIS TAKES TIME. you keep on filling it and filling it until it starts coming out, BUT before you call it full you MUST see the coolant circulationg. You will see it spurting out the tubes inside the radiator.

However if it doesn't have an actual radiator cap, which is not that unusual anymore, there will be an air bleed, most likely at the top of the Tstat housing, but not always. A 1997 vehicle should be as I described, and a Ford will be using a conventional cooling system, not a polypropylene or oil based system so what I said should apply.

Before investing all that money though, run a compression check just to make DAMN SURE you don't have a headgasket problem. They are more common than people think. If you DO need headgaskets, get Felpro Printoseals, the metal kind.

It will run better than ever, and I am not kidding. The metal gasket is usually thinner which will raise the theoretical compression ratio. If it's a V6 (likely) with hydraulic lifters there will be zero compression once you install them. Pull the ECM fuse to turn off the injectors and let it crank under that no load condition until it starts sounding like a car engine rather than an electric motor. Throw the fuse back in and start it but DO NOT touch the accelerator. Let it idle however rough, even if it stumbles and stalls, DO NOT rev the engine up.

After that you wil not only have a nice cool running engine, but more horsepower than you were used to. Believe me I have done it. Of course you only gain that if the new gaskets are thinner than the originals. The Printoseals usually are, they are the equivalent of shaving the heads.

J

97 Aerostar running hot
 

On Mon, 13 Aug 2012 10:56:47 -0700, "Guv Bob"
wrote:

OK, back to the beast again. On the road, temperature is just slightly above mid-range, where it has always been. When stopped with engine idling, the temp slowly increases. If I set for more than a few minutes, it approaches max full scale. When I drive off, it comes back to normal.

Another symptom - that may or may not be normal or related - is when I start up cold, it takes a good 10 minutes to come up to temperature. Other car takes about 2 minutes.

R/R fan clutch -- no change.

First, analyse the problem. It's a Ford (Found On Road Dead).

OK, lets go a little deeper. The engine temperature is fine at road
(highway?) speeds when the engine is working hard. The temperature
rises when the engine idles. Air flow over the engine will not keep
it cool, that's why they have radiators.

I have never encountered an air lock problem, but will admit that
others may have more experience.

This does not sound like a thermostat problem. With a faulty
thermostat I would expect the engine to run at an elevated temperature
while pulling a load, and cool off when idling. A problem I HAVE
encountered is a defective radiator core - the fins had broken free of
the tubes. Again, it would run cool at idle and overheat under load.

The symptoms sound like the fan is not moving enough air - at driving
speeds sufficient air is forced through the radiator to dissipate the
heat, at idle the air isn't moving fast enough. The three possible
causes are a slipping fan belt, a defective fan clutch (which you have
already replaced), or a fan in backwards. If the fan blades are
curved there is only one 'right' way for it to be installed. A friend
made that mistake once - and got the 'Mr. Badwrench' award.

PlainBill

97 Aerostar running hot
 

On Mon, 13 Aug 2012 22:21:40 -0700 (PDT), the renowned
wrote:


First of all in my cars, even though it is not recommended, fukum - pure an=
tifreeze.

Why would you do that? It's not nearly as effective at cooling as the
recommended water-antifreeze mixture (it gets worse as the glycol
concentration increases). It also freezes at a relatively high
temperature (10°F/-12°C)!

http://en.wikipedia.org/wiki/Ethylene_glycol

It boils at a much higher temperature, but that means your engine can
get much hotter than it was designed to run.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

97 Aerostar running hot
 

97 Aerostar running hot
 

They cannot be designed to fail open.

J

97 Aerostar running hot
 

On Wed, 15 Aug 2012 19:03:29 -0700 (PDT), wrote:

They cannot be designed to fail open.

J
That is an interesting point. I clearly recall thermostats that
either failed to close completely or opened at too low a temperature.
On the other hand, the usual thermostat design utilizes a wax pellet
that forces the valve open. I can't see any way to design that to
fail open.

Still, that is clearly not the problem in this case. As described,
the engine runs at near normal temperature while the van is in motion,
but overheats when stopped. I have seen that problem once - my
Father-in-law had disconnected the electric radiator fan on his Audi
because he didn't like the fact it ran after the engine was turned
off. The engine would stay at normal temperatures while it was in
motion, but overheat when standing - for example at a traffic light.

PlainBill

97 Aerostar running hot
 

Guv Bob wrote:
OK, back to the beast again. On the road, temperature is just
slightly above mid-range, where it has always been. When stopped
with engine idling, the temp slowly increases. If I set for more
than a few minutes, it approaches max full scale. When I drive off,
it comes back to normal.

Another symptom - that may or may not be normal or related - is when
I start up cold, it takes a good 10 minutes to come up to
temperature. Other car takes about 2 minutes.

R/R fan clutch -- no change.

Is there an electric fan which normally comes on when an engine driven fan is
not sufficient. That system could be inoperative.

97 Aerostar running hot
 

On Mon, 13 Aug 2012 10:56:47 -0700, "Guv Bob"
wrote:

OK, back to the beast again. On the road, temperature is just slightly above mid-range, where it has always been. When stopped with engine idling, the temp slowly increases. If I set for more than a few minutes, it approaches max full scale. When I drive off, it comes back to normal.

Another symptom - that may or may not be normal or related - is when I start up cold, it takes a good 10 minutes to come up to temperature. Other car takes about 2 minutes.

R/R fan clutch -- no change.


Sounds like an inadequate radiator or radiator fan to me. Consider
upgrading either of both.

?-)